This invention concerns a radial piston hydraulic engine.
Such radial piston hydraulic engine solutions are known in the state of the art, wherein a box section is rotated and to the box section is joined a distributor mounted to the same. The distributor is a so-called distributing valve, which includes borings made in the direction of the distributor bushing and opening from the distributor""s end face. There are inlet channels to the distributor and outlet channels from it. The inlet channels open in the distributor""s end face, as do the outlet channels. The respective channels of the distributing valve are alternately in connection with piston spaces, which piston spaces include pistons and pusher wheels connected with the pistons and adapted to move against a cam ring located in connection with the box section. Under these circumstances, some pistons are in the work stage and some are not. Those pistons which are in the work stage are supplied with a pressurised medium through the distributor""s channels and, correspondingly, those pistons which have bypassed the work stage remove oil through the distributor by way of the outlet channels of the distributor. The pusher wheels located in the pistons push against the cam ring located in the box section. The cam ring includes a wavelike shape, whereby the cam ring and the box section connected to it are rotated with the aid of the pusher wheels. To ensure optimum operation of the distributor, the distributor""s end face must be in a tight slide fit against that end face of the cylinder body wherein the channels leading to the piston spaces are located.
The application presents an improvement especially on the solution presented in the applicant""s earlier FI 942304 application. The structure according to the invention is especially concerned with such a radial piston hydraulic engine, wherein the cylinder body and the shaft 14 are immovably connected to one another, e.g. by a groove coupling, and in which structure the cylinder body and its associated shaft are non-rotary. In accordance with the invention, those cylinder spaces P1, P2 . . . of the cylinder body, which are connected with cylinder block 1, in connection with themselves include oil channels, which are further connected with the distributor in the end face of the cylinder body. In some of these cylinder body channels shut-off valves are located, which are controlled by pressure. According to the invention, the shut-off valves are pre-controlled as follows. A channel boring is made through the shaft, and from the boring in question a control is branched off into certain cylinder spaces and into the shut-off valves located in connection with these. The structure according to the invention includes at least one other boring, from which controls are branched off to other piston spaces of the cylinder block and into their shut-off valves. Some of the channels connected with cylinder spaces in the cylinder body are such which do no include shut-off valves, and pressurised oil is also conducted to these in operation. Thus, by using the control channels selectively, different connections and thus different combinations of volume flows are achieved.
The radial piston hydraulic engine in accordance with the invention is characterised in that which is stated in the claims.